Saws are used for cutting stock material such as wood, plastic, metal and the like to a desired shape and/or size. After extensive use, the blade of the saw may become worn and need replacing. Alternatively, a saw operator may switch from working with one material to another or may desire to alter the cutting action of the saw, and therefore may be similarly required to change the blade or the orientation of the blade of the saw.
Typically, saws that use a circular saw blade use a nut to mount the blade on a shaft that is rotated by the saw to rotate the blade. Typically, the blade is secured to the shaft by a nut. When the blade needs to be replaced or otherwise removed, the nut must be loosened and removed from the shaft to release the blade. However, the shaft typically freely rotates within the saw when power is not provided to the saw. As such, application of torque to the nut to remove the nut from the shaft will cause the shaft and blade to rotate unless the blade and/or shaft is prevented from rotating.
In the past, the operator would use an additional tool to stop the blade from rotating while torque is applied to the nut. In many instances, the second tool was a block of wood. Many operators would unplug the saw and engage a block of wood with the teeth of the saw blade to prevent it from rotating. With the saw blade engaging the block of wood, the operator could use a wrench to apply torque to the nut and loosen it. However, as the blade was uncovered, if the wrench were to slip from the nut, the exposed teeth of the saw blade provided the potential for minor cuts or injuries to the operator. Further, to attain leverage for loosening the nut, the operator may position his free hand against the block of wood. As such, should the wood or wrench slip, the operator's other hand could also potentially contact the blade and become injured.
U.S. Pat. No. 5,983,480 to Fontaine et al. has attempted to prevent these problems by providing a blade changing tool that uses an arcuate guard that engages a blade that includes a slot having two sidewalls and a bottom. The tool also includes two feet that project from one sidewall to abut the table of the saw to prevent the blade from rotating. However, the present inventors identified what they believe to be several drawbacks of the '486 patent as will be further evident from the present disclosure including (1) the tool provides only a single size arcuate slot which is only closely sized for a single size blade; (2) the tool includes a complex design such that it includes undercuts, which prevent the device from being manufactured from a straight-pull mold thereby increasing manufacturing costs; (3) as the engagement between the teeth of the blade and the tool is hidden within the slot and behind the two parallel sides, it can be difficult to determine if the tool has properly been engaged with the tool.
There exists, therefore, a need in the art for an improved blade changing tool that facilitates removal of the blade, but makes it easier to determine if the tool is properly engaging the blade, can be manufactured more efficiently, and/or can easily accommodate multiple blade sizes.